name_list = ["zhangsan","lisi","wangwu"]

my_list = [21,25,21,23,22,20]
my_list.append(31)
print(my_list)
my_list.extend([29,33,30])
print(my_list)
first = my_list[0]
print(first)
last = my_list[-1]
print(last)
index = my_list.index(31)
print(index)